


Day Eleven

by FellQueen (Nikasha)



Series: Kinktober 2019 [11]
Category: Undertale (Video Game)
Genre: Bad Dirty Talk, Established Relationship, M/M, Multi, Praise Kink, Sibling Incest, SpicyKustard, Spitroasting, Threesome, Underfell Papyrus (Undertale), Underfell Sans (Undertale)
Language: English
Status: Completed
Published: 2019-10-12
Updated: 2019-10-12
Packaged: 2020-12-09 13:56:07
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,309
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/20995919
Author URL: https://archiveofourown.org/users/Nikasha/pseuds/FellQueen
Summary: Day ElevenPrompt: SpitroastPairing: Spicykustard (Underfell Papyrus/Underfell Sans/Classic Sans)





	Day Eleven

**Author's Note:**

  * For [nilchance](https://archiveofourown.org/users/nilchance/gifts).

> Inspired by, and takes place in, nilchance’s ATTL universe. Go read that shit, it gives me life.
> 
> I did some mimicking of their writing style to try to make it feel like it actually fit into that story world. By the way, I’m remarkably terrible at coming up with puns. I didn’t even try.

Sans couldn’t help but be utterly bemused.  
For one thing, Red was actually keeping his damn hands to himself for once. For another, Edge was parked across from them on the bed, a look of concentration on his face.  
“Dude, we’re talking about sex, not a marriage agreement,” he finally managed to blurt out. Red’s silent chuckling at his back was not helping.  
Edge grimaced. “Yes, but this needs to be discussed thoroughly before we begin so—“  
Red groaned loudly, interrupting. “We discussed it to dust yesterday, boss,” he snapped. “Can we just get to the good shit already?”  
Sans tried to gentle Red’s typical blunt-edged words. “It’ll be fine. I know you’re worried, but we planned this out to the last letter. Fuck knows you probably stayed up the past three nights thinking through every tiny detail.”  
“He sure did,” Red snorted. Sans dug his fingers into Red’s phalanges, but he didn’t seem repentant.  
Edge sighed. “I know. Ok. Just for god’s sake, use the safe word if you need to.”  
Sans opened his mouth to say something about how they had basically hammered that rule into his skull, relax already, then recalled the way Red looked every time he asked Sans for permission. “Yeah, I got it.”  
Edge leaned in and their teeth met. It may not be the first time they had kissed, but just like then, it sparked with lust and Sans felt heat. Edge’s tongue pressed against his teeth and he was already opening his mouth to give him entrance, head tilting slightly to make it easier.  
Red was a familiar presence at his back, sharp fingertips pricking gently at his hips. Sans felt him shift and lean around, and realized he was getting a good angle on them making out. He felt his face flush with embarrassment.  
Red crooned at him. “That’s right, honey, just relax.” His hands moved to wander down Sans’s spine, then around to scrape gently at his ribs through his shirts. Sans shuddered. He was a little horrified when Edge retreated and he made a small protesting noise.  
Edge just pressed his tongue to Sans’s collarbone. Sans tilted his head out of the way, hands twitching before he grabbed the sides of Edge’s shirt.  
Red’s hand snuck up underneath to his spine and tickled across the vertebrae before continuing. Sans was momentarily bereft of Edge’s mouth, but it was for the good cause of getting his damn clothes off.  
Edge was still drawing his tongue over Sans’s neck and shoulder when Red’s hand snuck down the front of Sans’s shorts. He startled, jerking.  
“Heh, easy there,” Red murmured into the side of his skull. “A little tense, babe?”  
Sans snorted. “Oh, no, I’m loose as a goose over here. Just got a massage at the beauty parlor, still waiting for my maniped—“ He cut off into a quiet hiss as Red brushed across the head of his dick.  
“You were saying?”  
“Fuck you.”  
Sans could feel the vibration of Edge’s chuckling through his teeth against his bones. He had almost forgotten he was there, although how he could was a mystery when Edge was larger than life, warm as a blaze, and currently working a bitemark into his shoulder. It probably wouldn’t last the night, he wouldn’t do that without permission, but Sans was abstractly pleased nonetheless.  
Red gave a rough twist of his hand and Sans jolted, thrusting into his grip. “Fuck, baby, you’re so good.”  
Sans swallowed. “Can we move this along? Not that I’m complaining, but I need to speak with a manager.”  
“I am the manager,” Edge purred into Sans’s throat.  
Sans and Red both snickered.  
Edge leaned back while Red divested Sans of his shorts, and watched with an odd look in his eyes as Red bullied Sans around until he was on his hands and knees, glancing back at Edge over his shoulder.  
Sans didn’t think there was any uncertainty on his face, but Edge bridged over him to press their teeth together. It was so soft and sweet, it was almost painful. His soul throbbed.  
Red was surprisingly quiet as Edge nuzzled Sans, then straightened, bare hands brushing down his spine. He didn’t recall Edge removing his gloves, but he sure as hell wasn’t about to complain.  
Red cupped Sans’s face with his hand. “Doin’ alright there?” he asked, thumb caressing.  
Sans put a hand on Red’s shorts and tugged a bit. “Fucking stellar. Dick, please.”  
“Well, since you asked so nicely...” Red pulled out his cock, magic already hard and heavy in his palm.  
Sans tried not to swallow, but his mouth wasn’t getting the memo. He took Red in hand just as he felt long fingers pressing into his entrance.  
Sans paused, eyes closing. Red must have sent some silent words to Edge, because he didn’t move. After a moment, Edge murmured, “Sans?”  
“I’m fine.” He took a breath. They weren’t going to believe him unless he relaxed, so he took Red into his mouth and sucked.  
Red groaned, fingers curling against the curve of his skull. “There’s my sweetheart.”  
Sans couldn’t stifle the grunt as Edge’s finger pressed further into him. It was much longer than his or Red’s, and Sans was already getting wet thinking about how it was going to feel with more. Edge stroked him a bit, then pressed his free hand to Sans’s lower vertebrae as he slid in a second finger.  
Red, unfortunately, was free of distractions beyond Sans’s mouth. “Told you he could take more’n two fingers, boss,” he commented to Edge idly as he continued to pet Sans’s skull. “Haven’t tried a fist yet, though.”  
Edge made a noise. “Not today, brother.”  
Sans tried not to think too hard about Edge’s entire hand in his cunt, but the passing thought was enough to have him clenching on Edge’s fingers. In retaliation for bringing it up, Sans took his mouth off Red, holding his dick while he dragged his tongue up the underside.  
Red fell into making loud noises at that point.  
Edge managed two more fingers on the next pass and Sans’s back arched before he paused, trying to accept that sudden change in his body’s world. Stubbornly, he lifted his head and took Red down again, pushing until he could feel him at the back of his throat.  
Red stroked his skull again. “Hang on, sweetheart, just take it for a sec.”  
Sans was a little puzzled, but willing. He understood when Edge withdrew his fingers and he felt something much, much larger at his entrance.  
Edge was big. All that fucking around with Red had not prepared him for this, and even after getting stretched, there was a sweet burn bordering on pain as Edge started to press into him.  
Sans squeezed his eyes shut, but they opened again when he felt Red start gently moving his hips, grinding his dick across Sans’s tongue. He glanced up to see a soft look on Red’s face as he stared down at Sans. It was quickly wiped away and he just gave Sans a wicked grin. “You’re taking his dick so good, precious.”  
Sans shivered and felt Edge pause, hands come to rest on his hips.  
“Damn it, brother,” Edge griped, his voice tight. “Don’t listen to him, Sans.”  
Sans would have replied to that, but his mouth was currently occupied, so he just huffed. Red pushed a little further into him, and Sans paused before swallowing, taking short breaths through his nasal aperture that weren’t doing him much good. His head felt fuzzy.  
Edge stopped again. He leaned over Sans’s back and kissed between his shoulder-blades, which had Sans making an involuntary noise around Red’s cock that made Red moan. Sans felt Edge straighten and heard a slick noise as he felt Red throb against his tongue. He tried to glance upwards to get a peek, but Red was already pulling away from Edge.  
He grinned down at Sans. “Ready for the fun part, Sansy?”  
He tried to glare, but it was too soft at the edges and Red didn’t seem remotely perturbed.  
Edge’s voice was like liquid heat trailing down Sans’s spine as he murmured, “You’re doing amazing, Sans.” He anchored his grip on Sans’s hips and started to withdraw.  
It felt like it went on forever before Edge stopped again, Sans panting helplessly around Red and his cunt clenching greedily to try to draw Edge back in. Edge was all too happy to start pushing back into him again, a painfully slow pace that felt like Edge was savoring every inch of him, every second he was wrapped in Sans’s heat.  
Red started thrusting into Sans’s mouth and that pretty much had any train of thought successfully off its rails. The head of his dick was dangerously close to sliding down Sans’s throat again and he was somewhat grateful for the practice through college that had his gag reflex nonexistent.  
Then Edge was deep inside him and pressed right up against a spot that had Sans seeing stars.  
“There, boss,” Red commented, but he hadn’t needed to. Sans was twitching hard around Edge, hips jittering to grind him against that point. Edge chuckled and circled his hips for a bit, letting Sans enjoy the pressure.  
Red gently gripped his skull and Edged wrapped long fingers around his lower spine. Almost in tandem, they withdrew then began fucking into Sans, Red making filthy noises and words of praise that almost didn’t make sense anymore, but it was the sentiment that really counted. Edge was breathing hard against Sans’s spine, hot pants that sent shivers through him. The sounds of their cocks hitting into his mouth and cunt were obscene, and Sans felt his whole face flush blue.  
He was so full and warm. This should have felt fucked up and wrong, probably, but he just felt surrounded and safe. With Edge finally there, it felt complete.  
It was hard to say who got close first, but Red was the first to speak up, his namesake color spread across his face. “Fuck, sweetheart, I’m gonna come. Come in your mouth.”  
Sans pushed further, eyes watering at the pressure in his mouth and throat, but it was worth it to see Red break, voice squeaking into silence as he came into Sans’s mouth. His expression was blissful.  
Edge was slamming into him from behind, and without Red to counterbalance it, Sans was getting jolted forward. He leaned down to press his forehead against the sheets.  
Red ran his hands across his back. “Look at you,” he started, voice rough. “Taking him all in like that. I knew you could do it, but it’s still so fuckin’ much.”  
Sans swallowed a whine, but couldn’t keep himself from squeezing down on Edge. Sharp fingers momentarily tightened on his hips before loosening again. Edge was ever so careful, even while plowing into Sans.  
Edge managed to hit just the right angle again and Sans was gone, head snapping up as he shouted and clenched down on Edge. It dragged Edge down with him, although he managed to grunt out a warning.  
Sans shuddered as he felt Edge’s magic pulsing into him, Edge continuing to fuck into him through it. He finally slowed and stopped, leaning over to wrap his arms around Sans.  
It was quiet for a moment, the three of them catching their breath.  
“Fuck that was great,” Red suddenly purred. He tilted Sans’s face up and kissed him. Sans gave him as much of his own taste off his tongue as he could. Red didn’t seem to mind.  
Edge pulled out slowly, then Sans heard the soft noise of magic dissipating. He glanced back to see Edge looking down at his cunt with a expression of rapture and he wasn’t entirely surprised when Edge bent down to lick the red and blue cum leaking back out of him. He still yelped, trying to jerk his sensitive cunt away from the tongue against it, but Edge kept him in place with a grip on his femur.  
Red snickered. “You have no idea how long he’s been wantin’ to do that,” he whispered conspiratorially to Sans.  
Sans had the thought that he probably didn’t want to know.  
Despite being the less experienced one in the relationship, Edge was decent with his tongue. He had Sans riled up again quickly, small drags over his clit that had him gasping and biting at the sheets. Red stroked his skull and murmured praise to him as Edge got him to come again, shaking to pieces.  
Sans felt the bed shift as Edge got up and had an unexpected stab of disappointment. He looked at Edge’s back, then up to Red.  
Red laughed and ignored the silent question, pulling Sans up towards the pillows and lying down in front of him, burying his face in Sans’s shoulder and sighing happily.  
Sans cuddled into Red, but looked up again to see what Edge was up to.  
Turned out it wasn’t anything drastic. The edgelord just got undressed and folded his clothes before coming back to bed, crawling over Sans and Red and giving a fantastic view of his pelvis before settling in behind Sans, arm resting across his hip and finding Red.  
“Brother, you could at least undress,” Edge sighed.  
Red gave a very unconvincing snore.  
Edge chuckled against the back of Sans’s skull.  
“Mmh, you good, edgelord?” Sans asked, his words slipping out loosely. He wasn’t quite as out of it as he had been a few times, but that fuzzy feeling hadn’t quite gone away.  
Edge nuzzled him. “Perfectly.”  
“Go to sleep, assholes,” Red complained, completely coherent.  
“No assholes here,” Sans remarked sleepily. “Grand total of zilch. Try again.”  
“Shut up.”  
Edge just laughed softly and thumbed the collar on Sans’s wrist, the one Red was already holding.

**Author's Note:**

> List used: https://twitter.com/idek_uggy/status/1178349575725174786?s=21
> 
> Tomorrow is forced chastity


End file.
